Preparation of fluorinated benzonitrile

Abstract

Abstract PURPOSE:To obtain the titled compound in high yield, by reacting a nucleus- chlorinated benzonitrile with potassium fluoride in dimethyl sulfoxide with controlling the reaction temperature with the progress of the reaction. CONSTITUTION:A nucleus-chlorinated benzonitrile is reacted with potassium fluoride in a solvent of dimethyl sulfoxide, the temperature is kept at <=165 deg.C until the nucleus halogen substitution ratio reaches at least 35%, and the reaction is then completed at high temperature of >=165 deg.C to give a fluorinated benzonitile. The reaction rate of high-boiling by-product is suppressed by controlling the reaction temperature at two stages in the solvent, and since a large amount of potassium fluoride is present in the reaction system at the early stage of the reaction, the reaction is advanced at low temperature (preferably at 130-165 deg.C), so the final yield can be raised. The fluorine substitution ratio is obtainable by using part of the reaction solution by gas chromatography, etc.

Inventors

• 👤 Masakatsu Nishimura
• 👤 西村　正勝
• 👤 Yasuhiko Hirai
• 👤 平井　保彦

Bibliographic Details